THE downside of being heavily engaged in any demanding job – lawyer, doctor, surveyor, plumber, manager – is that you become immersed in your clients' problems.

You lose sight of the larger picture. The same is true for teachers, civil servants, judges, politicians. Eyes are firmly fixed on the ground, brains calculating the next step; you seldom look to see what lies on the horizon, or what is happening on either side; there's no time to look back. You fail to see the wood because you are preoccupied with the roots of the trees.

We take notice of the wider world only when it comes up and bites us on the leg. Your dentist retires and you suddenly discover that there is a nationwide shortage of NHS dentists. You go to the airport and terrorist alert delays your flight, all because of some sectarian dispute in an unknown faraway country whose name you can't even pronounce. You go to buy haddock only to discover that the fishing grounds have been closed because the species is threatened with extinction. You hear about Britney's self-inflicted wounds but turn a deaf ear to news of man-made famine in Burundi.

But it is salutary, indeed essential, occasionally to turn aside from the daily grind, the trivia of celebrity, the aridity of routine, and accept the challenge of trying to understand something of the great intellectual and historical forces that have shaped our world and continue to do so.

It is not enough just to worry about the present or to fret about the future: it is essential to reflect on the past. Our lives are shaped by the history, not just of events but, more importantly, of ideas. If we don't understand that – if we imagine that kings, battles and empires alone are what fashioned our civilisation – then we simply fail to understand the society in which we live.

For lawyers especially, it is essential to appreciate that the laws that govern our lives derive from the ideas, the sacrifices and the struggles of those who employed their reason to challenge the myths that supported tyrannies, whether of the mind or of governance.

It is not difficult to rediscover where we came from: just switch off the TV, bin the colour supplements, the "Style" and "Escape" sections of the Sunday paper, and settle down to read a book – one that illuminates how Western civilisation was made, a book that reminds us how we won the right to freedom of conscience and thought, and the power to fashion our social, intellectual and political environment.

So let me recommend an outstanding account of where our liberties really came from. It explains: why we are no longer burned at the stake or beheaded for rejecting the doctrines of the religious establishment; how we won the right to reject the faith-based orthodoxies that the Earth was the centre of the universe and that women were fashioned from Adam's spare rib some five millennia ago.

It is a story of the bravery and sacrifices of those who – often at the cost of their lives – challenged the myths and superstitions of their times, cruelly and stubbornly promulgated by tyrants of the mind: the last judicial execution for blasphemy in Scotland was in 1697. It is a challenging affirmation of the maxim "The price of liberty is eternal vigilance". It could, frighteningly, be easier to lose our intellectual and spiritual freedom than it was to win it.

This story is narrated in A C Grayling's outstanding book, Towards the Light. It is not a history of events but it reminds us of familiar happenings. They include the murderous persecutions by the Spanish Inquisition, the Reformation, the French and American Revolutions and the campaigns for the abolition of slavery.

It charts the reasoned and evidence-based analyses that underlay the intellectual struggles for freedom of thought in Western society that reached their apogee in the Enlightenment, in which Scots played an outstanding role. It tells how religious reformers, scientists, political philosophers and even lawyers won for us all the right to think for ourselves, to accept or reject religious beliefs, and to discard political systems that exerted tyranny over the many to benefit a privileged few.

The fruits of their endeavours were not only books and political tracts but also the prolonged – and unfinished – battles to overcome the prejudices, cultural practices and beliefs that, for thousands of years, have helped to make the lives of women, slaves, the industrial and agricultural underclasses, and the mentally ill and dissidents or eccentrics of all kinds inexcusably miserable. Lawyers can take pride in the lawyer-heroes, Lincoln, Gandhi and Mandela.

If the results are to be celebrated, as they should be, then equally the sustained, numbing obstinacy of those who blocked the paths to liberty of mind and conscience must leave us puzzled and dismayed at the lack of openness of mind of so many who wielded power for centuries in medieval Europe.

If we are to be worthy of the achievements of those who previously lit the way out of intellectual darkness, then it is for us to remember their achievements, to salute and safeguard them. Those intellectual achievements are significantly more important constituents of our heritage than the castles, the stately homes, the ceremonials – even the literature – that we rightly preserve as proclaiming our identity.

So it is for us all, not least lawyers and politicians, to rediscover whose shoulders we stand upon when – usually without conscious acknowledgement – we affirm and seek to vindicate the rights of clients, of citizens. Let us remember where rights came from and what they cost. We have a solemn responsibility to treasure and preserve them. As always in troubled times, they are under threat.